This invention relates generally to an image forming device and more particularly to an image forming device which exposes a photosensitive member to an optical image and transfers the image to a sheet of paper.
Various methods of forming images using photosensitive materials which harden or soften when exposed to light are disclosed in U.S. Pat. No. 3,219,446 and Japanese Patent Laid-Open Nos. 88739/83 and 30537/84. Each of these methods employs photosensitive materials which are transferred. The creation of images requires control of the transferability of these materials. Subsequent to exposure, these methods involve simpler steps than a silver salt photographic method and offer better image quality by gradation than electrophotography.
Conventional methods which utilize photosensitive materials which harden or soften when exposed to light employ development devices which apply constant pressure. However, depending on the width, thickness and the quality of the paper on which the image is reproduced, as the image concentration changes, the homogeneity of the concentration is lost, and creases are produced.
In conventional methods, when the power is turned off by the operator or the power fails, the paper overheats and scorches or decomposes resulting in the production of poisonous gases. Irritating gases are also produced during normal operation of conventional image forming devices.
Accordingly, it is desirable to provide an image forming device which varies pressure during development, does not overheat the paper when the power is turned off and which has a device for removing gas produced during the development process.